xref: /openbmc/linux/drivers/input/matrix-keymap.c (revision 656d29ce)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Helpers for matrix keyboard bindings
4  *
5  * Copyright (C) 2012 Google, Inc
6  *
7  * Author:
8  *	Olof Johansson <olof@lixom.net>
9  */
10 
11 #include <linux/device.h>
12 #include <linux/export.h>
13 #include <linux/gfp.h>
14 #include <linux/input.h>
15 #include <linux/input/matrix_keypad.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/property.h>
19 #include <linux/slab.h>
20 #include <linux/types.h>
21 
matrix_keypad_map_key(struct input_dev * input_dev,unsigned int rows,unsigned int cols,unsigned int row_shift,unsigned int key)22 static bool matrix_keypad_map_key(struct input_dev *input_dev,
23 				  unsigned int rows, unsigned int cols,
24 				  unsigned int row_shift, unsigned int key)
25 {
26 	unsigned short *keymap = input_dev->keycode;
27 	unsigned int row = KEY_ROW(key);
28 	unsigned int col = KEY_COL(key);
29 	unsigned short code = KEY_VAL(key);
30 
31 	if (row >= rows || col >= cols) {
32 		dev_err(input_dev->dev.parent,
33 			"%s: invalid keymap entry 0x%x (row: %d, col: %d, rows: %d, cols: %d)\n",
34 			__func__, key, row, col, rows, cols);
35 		return false;
36 	}
37 
38 	keymap[MATRIX_SCAN_CODE(row, col, row_shift)] = code;
39 	__set_bit(code, input_dev->keybit);
40 
41 	return true;
42 }
43 
44 /**
45  * matrix_keypad_parse_properties() - Read properties of matrix keypad
46  *
47  * @dev: Device containing properties
48  * @rows: Returns number of matrix rows
49  * @cols: Returns number of matrix columns
50  * @return 0 if OK, <0 on error
51  */
matrix_keypad_parse_properties(struct device * dev,unsigned int * rows,unsigned int * cols)52 int matrix_keypad_parse_properties(struct device *dev,
53 				   unsigned int *rows, unsigned int *cols)
54 {
55 	*rows = *cols = 0;
56 
57 	device_property_read_u32(dev, "keypad,num-rows", rows);
58 	device_property_read_u32(dev, "keypad,num-columns", cols);
59 
60 	if (!*rows || !*cols) {
61 		dev_err(dev, "number of keypad rows/columns not specified\n");
62 		return -EINVAL;
63 	}
64 
65 	return 0;
66 }
67 EXPORT_SYMBOL_GPL(matrix_keypad_parse_properties);
68 
matrix_keypad_parse_keymap(const char * propname,unsigned int rows,unsigned int cols,struct input_dev * input_dev)69 static int matrix_keypad_parse_keymap(const char *propname,
70 				      unsigned int rows, unsigned int cols,
71 				      struct input_dev *input_dev)
72 {
73 	struct device *dev = input_dev->dev.parent;
74 	unsigned int row_shift = get_count_order(cols);
75 	unsigned int max_keys = rows << row_shift;
76 	u32 *keys;
77 	int i;
78 	int size;
79 	int retval;
80 
81 	if (!propname)
82 		propname = "linux,keymap";
83 
84 	size = device_property_count_u32(dev, propname);
85 	if (size <= 0) {
86 		dev_err(dev, "missing or malformed property %s: %d\n",
87 			propname, size);
88 		return size < 0 ? size : -EINVAL;
89 	}
90 
91 	if (size > max_keys) {
92 		dev_err(dev, "%s size overflow (%d vs max %u)\n",
93 			propname, size, max_keys);
94 		return -EINVAL;
95 	}
96 
97 	keys = kmalloc_array(size, sizeof(u32), GFP_KERNEL);
98 	if (!keys)
99 		return -ENOMEM;
100 
101 	retval = device_property_read_u32_array(dev, propname, keys, size);
102 	if (retval) {
103 		dev_err(dev, "failed to read %s property: %d\n",
104 			propname, retval);
105 		goto out;
106 	}
107 
108 	for (i = 0; i < size; i++) {
109 		if (!matrix_keypad_map_key(input_dev, rows, cols,
110 					   row_shift, keys[i])) {
111 			retval = -EINVAL;
112 			goto out;
113 		}
114 	}
115 
116 	retval = 0;
117 
118 out:
119 	kfree(keys);
120 	return retval;
121 }
122 
123 /**
124  * matrix_keypad_build_keymap - convert platform keymap into matrix keymap
125  * @keymap_data: keymap supplied by the platform code
126  * @keymap_name: name of device tree property containing keymap (if device
127  *	tree support is enabled).
128  * @rows: number of rows in target keymap array
129  * @cols: number of cols in target keymap array
130  * @keymap: expanded version of keymap that is suitable for use by
131  * matrix keyboard driver
132  * @input_dev: input devices for which we are setting up the keymap
133  *
134  * This function converts platform keymap (encoded with KEY() macro) into
135  * an array of keycodes that is suitable for using in a standard matrix
136  * keyboard driver that uses row and col as indices.
137  *
138  * If @keymap_data is not supplied and device tree support is enabled
139  * it will attempt load the keymap from property specified by @keymap_name
140  * argument (or "linux,keymap" if @keymap_name is %NULL).
141  *
142  * If @keymap is %NULL the function will automatically allocate managed
143  * block of memory to store the keymap. This memory will be associated with
144  * the parent device and automatically freed when device unbinds from the
145  * driver.
146  *
147  * Callers are expected to set up input_dev->dev.parent before calling this
148  * function.
149  */
matrix_keypad_build_keymap(const struct matrix_keymap_data * keymap_data,const char * keymap_name,unsigned int rows,unsigned int cols,unsigned short * keymap,struct input_dev * input_dev)150 int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
151 			       const char *keymap_name,
152 			       unsigned int rows, unsigned int cols,
153 			       unsigned short *keymap,
154 			       struct input_dev *input_dev)
155 {
156 	unsigned int row_shift = get_count_order(cols);
157 	size_t max_keys = rows << row_shift;
158 	int i;
159 	int error;
160 
161 	if (WARN_ON(!input_dev->dev.parent))
162 		return -EINVAL;
163 
164 	if (!keymap) {
165 		keymap = devm_kcalloc(input_dev->dev.parent,
166 				      max_keys, sizeof(*keymap),
167 				      GFP_KERNEL);
168 		if (!keymap) {
169 			dev_err(input_dev->dev.parent,
170 				"Unable to allocate memory for keymap");
171 			return -ENOMEM;
172 		}
173 	}
174 
175 	input_dev->keycode = keymap;
176 	input_dev->keycodesize = sizeof(*keymap);
177 	input_dev->keycodemax = max_keys;
178 
179 	__set_bit(EV_KEY, input_dev->evbit);
180 
181 	if (keymap_data) {
182 		for (i = 0; i < keymap_data->keymap_size; i++) {
183 			unsigned int key = keymap_data->keymap[i];
184 
185 			if (!matrix_keypad_map_key(input_dev, rows, cols,
186 						   row_shift, key))
187 				return -EINVAL;
188 		}
189 	} else {
190 		error = matrix_keypad_parse_keymap(keymap_name, rows, cols,
191 						   input_dev);
192 		if (error)
193 			return error;
194 	}
195 
196 	__clear_bit(KEY_RESERVED, input_dev->keybit);
197 
198 	return 0;
199 }
200 EXPORT_SYMBOL(matrix_keypad_build_keymap);
201 
202 MODULE_LICENSE("GPL");
203